Liquid Crystal Display Device

ABSTRACT

A liquid crystal display device includes a TFT substrate having an organic passivation film, and a counter substrate, with liquid crystals inside of the liquid crystal display device. A columnar spacer is formed on the counter substrate, which defines a distance between the TFT substrate and the counter substrate, and a concavo-convex pedestal is formed in a pixel region of the TFT substrate, the concavo-convex pedestal being provided in facing relation to the columnar spacer. The concavo-convex pedestal is formed with a convex portion and a concave portion at a bottom of the concavo-convex pedestal, with a top end of the columnar spacer being in contact with two or more convex portions formed on the bottom of the concavo-convex pedestal, and an area at the bottom of the concavo-convex pedestal being larger than the area at the top end of the columnar spacer.

CLAIM OF PRIORITY

The present application claims priority from Japanese Patent ApplicationJP 2011-128815 filed on Jun. 9, 2011, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device. Theinvention more particularly relates to a liquid crystal display deviceconfigured to take a countermeasure against light spots attributable toshavings of an alignment film.

2. Description of the Related Art

Liquid crystal display devices include a TFT substrate having pixelelectrodes, thin film transistors (TFT), etc. formed in a matrix; acounter substrate disposed in facing relation to the TFT substrate andhaving color filters, etc. formed at positions corresponding to thepixel electrodes of the TFT substrate; and liquid crystals put betweenthe TFT substrate and the counter substrate. Images are formed bycontrolling the light transmittance of liquid crystal molecules of eachpixel.

In a liquid crystal display device, an alignment film is formed at theboundary surface of the counter substrate and a liquid crystal layer ofthe TFT substrate and liquid crystal molecules are subjected to initialalignment by applying a rubbing process or an optical alignment processto the alignment film. Then, an amount of light transmitted through theliquid crystal layer is controlled by twisting or rotating the liquidcrystal molecules from the initial alignment by an electric field.

On the other hand, for controlling the thickness of the liquid crystallayer, it is necessary to form a spacer between the counter substrateand the TFT substrate. While beads, etc. were conventionally dispersedas a spacer in the liquid crystal layer, columnar spacers have beenformed on the counter substrate to control a gap between the TFTsubstrate and the counter substrate by the columnar spacers in recentyears in order to control the gap (liquid crystal layer) more exactly.

On the other hand, an additional problem occurs by using the columnarspacer. For example, JP-A-2005-242297 describes that a frictional forceis decreased when the columnar spacer is displaced in a case of pressingthe counter substrate from the outside so that the columnar spacer caneasily return to the initial place when the external pressure isremoved. For this purpose, JP-A-2005-242297 discloses that a pedestalhaving an area smaller than that at the top end of the columnar spaceris formed as a pedestal which is formed on the TFT substrate.

Further, a problem of generating shavings of the alignment film alsooccurs when the columnar spacer displaces laterally. Other documentsconcerning scraping of the alignment film or columnar spacers includeJP-A-2007-328247, JP-A-2008-170690, JP-A-2009-58618, JP-A-2009-282262,JP-A-2010-8616, and JP-A-Hei 5-107545. It is to be noted thatJP-A-2005-242297 corresponds to U.S. Pat. No. 7,502,090, JP-A-2009-58618corresponds to USP 2009/0059155, and JP-A-2009-282262 corresponds to USP2011/0080548.

SUMMARY OF THE INVENTION

Generally, the columnar spacers are disposed to the counter substrate.On the other hand, the pedestals are disposed to the TFT substrate atpositions provided in facing relation to the columnar spacers. Thepedestal means herein not only those having a protruding portion formedon the side of the TFT substrate but also those planarized or concavedat a portion provided in facing relation to the columnar spacer. Thatis, the pedestal means herein the structure on the side of the TFTsubstrate provided in facing relation to the columnar spacer.

In the liquid crystal display device, an alignment film is formed on thesurface of the counter substrate and the TFT substrate in contact withthe liquid crystal layer. Since the columnar spacer has a relativelylarge height, the alignment film is less formed at the top end of thecolumnar spacer in the counter substrate. On the other hand, since theheight of the pedestal of the TFT substrate is lower than that of thecolumnar spacer, the alignment film is formed also on the surface of thepedestal. When the columnar spacer is in contact with the surface of thepedestal on which the alignment film is formed, the alignment film atthe surface of the pedestal is scraped off.

That is, when the liquid crystal display device undergoes temperaturecycles, etc. and the TFT substrate and the counter substrate expand orshrink at different ratios or when the counter substrate undergoes apressure from the outside, the columnar spacer displaces laterally. Atthis time, the alignment film on the pedestal is scraped off. Whenscraped off shavings of the alignment film intrude into the liquidcrystal layer, light spots are generated to degrade the image quality.

The present invention intends to suppress the generation of the lightspots by providing a countermeasure for the scraped off shavings of thealignment film caused by the columnar spacer.

The present invention intends to overcome the problem described aboveand provides a liquid crystal display device comprising:

a TFT substrate having an organic passivation film;

a counter substrate, the counter substrate being adhered to the TFTsubstrate by a sealant formed at a periphery thereof;

liquid crystals put inside of the liquid crystal display device;

a columnar spacer formed on the counter substrate, the columnar spacerdefining a distance between the TFT substrate and the counter substrate;and

a concavo-convex pedestal formed in a pixel region of the TFT substrate,the concavo-convex pedestal being provided in facing relation to thecolumnar spacer;

wherein the concavo-convex pedestal is formed with a convex portion anda concave portion at a bottom of the concavo-convex pedestal, and theheight of the top end of the convex portion is lower than that of theplanar portion,

wherein the thickness of the alignment film present on the convexportion is smaller than the thickness of the alignment film present onthe concave portion,

wherein the top end of the columnar spacer is in contact with two ormore convex portions formed on the bottom of the concavo-convexpedestal, and

wherein the area at the bottom of the concavo-convex pedestal is largerthan the area at the top end of the columnar spacer.

According to the invention, in the liquid crystal display device havingthe columnar spacer and using the optical alignment film, since scrapingof the alignment film caused by the columnar spacer can be prevented,production yield of the liquid crystal display device can be improved.Further, since scraping of the alignment film, which is caused by thelateral displacement of the columnar spacer attributable to thetemperature cycles after shipping or the pressure from the outside tothe counter substrate, can be prevented, generation of failure in themarket can be prevented.

In a liquid crystal display device of a liquid crystal injection typeusing a dropping method, the number of columnar spacers is small and astress between the columnar spacer and the pedestal per one set islarge. According to the invention, since the alignment film is notpresent or the film thickness is smaller than that in other portions inthe pedestal in contact with the columnar spacer, generation of thescraping of alignment film can be prevented. Thus, generation of lightspots can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a liquid crystal display device ofthe invention.

FIG. 2 is a cross sectional view of a liquid crystal display device of acomparative embodiment to the invention.

FIG. 3 is a cross sectional view of a liquid crystal display deviceshowing a state where a TFT substrate and a counter substrate aredeformed inwardly into a convex shape.

FIG. 4 is a perspective view showing an example of a convex portionformed at the bottom of a concavo-convex pedestal.

FIG. 5 is a schematic cross sectional view for defining the angle ofinclination of the convex portion formed at the bottom of theconcavo-convex pedestal.

FIG. 6 is a cross sectional view showing a state where the convexportion formed at the bottom of the concavo-convex pedestal and thecolumnar spacer are in contact to each other.

FIG. 7 is a plan view showing a region where the concavo-convex pedestalis formed.

FIG. 8 is a perspective view showing a shape at the bottom of theconcavo-convex pedestal according to an Embodiment 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a cross sectional view of a liquid crystal display deviceaccording to the invention. FIG. 2 is a schematic cross sectional viewof a liquid crystal display device as a comparative embodiment. Firstdescription is to be made with reference to FIG. 2.

In FIG. 2, an organic passivation film 101 is formed over a TFTsubstrate 100. Since the organic passivation layer 101 also has afunction as a planarizing film, it is formed to a large thickness ofabout 1.5 to 2 μm. In FIG. 2, while interconnects, electrodes,semiconductor films, a gate insulating film, an inorganic passivationfilm, etc. are formed actually between the TFT substrate 100 formed ofglass and the organic passivation film 101, the layers are notillustrated since FIG. 2 is a schematic view.

The organic passivation film 101 per se is formed of a photosensitiveresin and can be patterned without using a photoresist. A hole or aconcave portion is formed on the organic passivation film 101 by usingexposure or half exposure. The organic passivation film 101 is removedfrom a portion of forming a sealant 140 for bonding the TFT substrate100 and the counter substrate 200. Further, a concave pedestal 120 isformed on the TFT substrate 100 at a portion provided in facing relationto the columnar spacer 150 formed on the counter substrate 200. Theconcave pedestal 120 is concaved at a portion of the TFT substrate 100in contact with the columnar spacer 150 and is lowered compared withother portions.

The concave pedestal 120 is formed as described above in order to keepthe TFT substrate 100 or the counter substrate 200 to an inwardlyconvexed shape in a usual state. For example, in the structure as shownin FIG. 3, when temperature increases and the TFT substrate 100 or thecounter substrate 200 expands thermally, the stress caused by thethermal expansion exerts in the direction as shown by F in FIG. 3 andthis is not a direction of causing a gap between the TFT substrate 100and the counter substrate 200. Accordingly, even when the TFT substrate100 or the counter substrate 200 thermally expands, bubbles are notgenerated in the liquid crystal layer.

Referring again to FIG. 2, since the concave pedestal 120 is formed in apixel region DI in the inside of the sealant 140 in FIG. 2 and theplanar pedestal 110 is formed at the outside PE of the sealant 140, thegap between the TFT substrate 100 and the counter substrate 200 isdecreased in the pixel region DI and the liquid crystal display devicehas a shape as shown in FIG. 3.

While a counter electrode, an interlayer insulating film, a pixelelectrode, etc. are formed usually over the organic passivation film 101of the TFT substrate 100, since FIG. 2 is a schematic view, the layersare not illustrated. Accordingly, in FIG. 2, the alignment film 105 isformed over the organic passivation film 101. Since the alignment film105 is liquid at the instance it is coated, it accumulates at a largethickness in the lower portion by the leveling effect.

That is, the alignment film 105 is formed at a relatively largethickness also on the concave pedestal 120 shown in FIG. 2. Thealignment film 105 is not coated to a portion where the sealant 140 isformed. Since the adhesion between the sealant 140 and the substrate islowered when the alignment film 105 is present at the sealant 140,deposition of the alignment film 105 to the sealant 140 is prevented byusing a stopper or the like.

In FIG. 2, an overcoat film 201 is formed on the side of the countersubstrate 200, and the columnar spacer 150 is formed over the overcoatfilm 201. While color filters and black matrixes are generally formedbetween the overcoat film 201 and the counter substrate 200, since FIG.2 is a schematic view, they are not illustrated. The alignment film 105is formed over the overcoat film 201. In FIG. 2, the alignment film 105is not formed at the top end of the columnar spacer 150. This is becausethe columnar spacer 150 has a relatively large height and the alignmentfilm 105, which is liquid during coating, is less deposited at the topend. Also on the side of the counter substrate 200, the alignment film105 is not formed on the sealant 140 by the same reason as that for theTFT substrate 100.

In FIG. 2, while the columnar spacer 150 of the counter substrate isdisposed in facing relation to the portion of the concave pedestal 120of the TFT substrate 100, the alignment film 105 is present on theconcave pedestal 120. Therefore, when the columnar spacer 150 causeslateral displacement, etc., the alignment film 105 is scraped off togenerate scraped off shavings of the alignment film and cause lightspots. In the invention shown by the following embodiments, scraping ofthe alignment film 105 can be prevented in the liquid crystal displaydevice having the concave pedestal 120 in the pixel region DI.

Embodiment 1

FIG. 1 is a cross sectional view of a liquid crystal display deviceaccording to the invention. The basic configuration of FIG. 1 isidentical with that in FIG. 2. That is, a concave pedestal is formed onthe organic passivation film 101 in the pixel region so that the TFTsubstrate 100 and the counter substrate 200 are convexed inward as shownin FIG. 3 to make the gap between the TFT substrate 100 and the countersubstrate 200 smaller in the pixel portion than in the periphery.

FIG. 1 is different from FIG. 2 in that a concavo-convex portion isformed at the bottom of the concave pedestal for preventing scraping ofthe alignment film by the columnar spacer 150. The pedestal in FIG. 1 ishereinafter referred to as a concavo-convex pedestal 130. That is, inthe concavo-convex pedestal 130, the concavo-convex portion is formed atthe bottom of the concave pedestal 120 formed on the organic passivationfilm 101.

In FIG. 1, while a convex portion 131 and a concave portion 132 areformed at the bottom of the concavo-convex pedestal 130, the columnarspacer 150 formed on the counter substrate 200 is in contact only withthe convex portion (corresponding to the portion 131 in FIG. 4 to bedescribed later) of the concavo-convex pedestal 130.

In order to make the cross sectional shape of the liquid crystal displaydevice into the shape as shown in FIG. 3, the height of the convexportion 131 at the bottom of the concavo-convex pedestal 130 is lowerthan the height of the planar pedestal 110 at the outside of the sealant140. Alternatively, the height of the convex portion 131 at the bottomof the concavo-convex pedestal 130 is lower than that of the planarportion between adjacent concavo-convex pedestals 130 and 130.

The alignment film 105 is not present on the convex portion 131 due tothe leveling effect or, even if it is present, the thickness is madeextremely smaller than that of the concave pedestal portion in FIG. 2.Accordingly, even when lateral displacement is caused to the columnarspacer 150, the alignment film 105 is not scraped off. On the otherhand, while the alignment film 105 is present on the concave portion 132of the concavo-convex pedestal 130, the columnar spacer 150 is not incontact with the concave portion 132 of the concavo-convex pedestal 130in the configuration of the present invention.

FIG. 4 is a schematic view for the shape of the bottom of theconcavo-convex pedestal 130, which is a perspective view of the convexportion 131 as a protrusion having a circular bottom. The concaveportion 132 is present between adjacent convex portions 131 and 131.While more convex portions 131 are usually formed at the bottom of theconcavo-convex pedestal 130, FIG. 4 shows a portion of the bottom.

FIG. 5 is a cross sectional view along line A-A in FIG. 4 which showsthe definition for the angle of inclination θ of the convex portion 131formed at the bottom of the concavo-convex pedestal 130. In FIG. 5, theangle of inclination θ means an angle between the planar concave portion132 and a line connecting the apex of the concave portion 131 and abeginning portion of a planar concave portion 132. When it is uncertainwhether the concave portion 132 is planar or not, a line connecting twoconcave portions 132 on the both sides of the convex portion 131 may bedefined as a flat line.

The convex portion 131 is formed by using half exposure. That is, theconcavo-convex portion is formed at the bottom of the concavo-convexpedestal 130 by decreasing the exposure amount for the convex portion131 and increasing the exposure amount for the concave portion 132. Insuch a forming method, it is difficult to form a large angle ofinclination θ as shown in FIG. 5. On the other hand, when θ isexcessively small, it is difficult to form sufficient concavo-convexportion in order not to form the alignment film 105 on the concaveportion 131.

As the condition for the angle in order not to form the alignment film105 to the convex portion by the process for forming the concavo-convexportion and due to the leveling effect of the concavo-convex portion, θis desirably 3 degrees or more and 45 degrees or less in FIG. 5according to the experiment.

When θ is smaller than 3 degrees, the effect of decreasing the thicknessof the alignment film 105 on the concave portion 131 was not obtained.As the effect of the invention, a predetermined effect can be obtainednot only in the case where the alignment film 105 is eliminatedcompletely at the convex portion 131 but also in the case where thethickness of the alignment film 105 at the concave portion 131 isdecreased to less than that in the concave portion. The value for the θis more preferably 6 degrees or more and 25 degrees or less.

FIG. 6 is a cross sectional view showing the state where the columnarspacer 150 is in contact with the concavo-convex pedestal 130 at thebottom of the concavo-convex pedestal. In the TFT substrate 100 in FIG.6, layers below the organic passivation film 101 are not illustrated.The organic passivation film 101 is formed at a thickness of 1.5 μm. Theconcavo-convex portion is formed on the organic passivation film 101 andan interlayer insulating film 102 formed of SiN is formed over theorganic passivation film 101.

A metal layer 103 inherent to the pedestal portion is formed of a metalover the interlayer insulating film 102. The metal layer 103 is formedof MoCr. It is to be noted that the metal layer 103 is disposed foradjusting the height of the portion in contact with the columnar spacer150, which is not essential depending on the place. An ITO(Indium-Tin-Oxide) film 104 is formed on a thickness of 77 μm over themetal layer 103 by sputtering. The ITO film 104 is formed simultaneouslywith sputtering for the pixel electrode. While the alignment film 105 isformed over the ITO film 104, the alignment film 105 is deposited suchthat the thickness is 80 μm for the planar portion between adjacentconcavo-convex pedestals 130 and 130 in FIG. 1.

In this case, at the bottom of the concavo-convex pedestal 130 shown inFIG. 6, the alignment film 105 is not present on the convex portion 131and the alignment film 105 is present only on the concave portion 132.As shown in FIG. 6, the top end of the columnar spacer 150 is in contactonly with the convex portions 131 at the bottom of the concavo-convexpedestal 130. Since the alignment film 105 is not present on the convexportions 131 in contact with the columnar spacer 150, if the columnarspacer 150 should cause lateral displacement, etc., the alignment film105 is not scraped off.

What is important in FIG. 6 is that the top end of the columnar spacer150 is in contact with at least two convex portions 131 formed at thebottom of the concavo-convex pedestal 130. If the top end of thecolumnar spacer 150 is in contact only with one convex portion 131,since the columnar spacer 150 is tilted and a portion thereof is incontact with the concave portion 132 where the alignment film 105 isformed at a large thickness, the alignment film 105 tends to be scrapedoff.

In FIG. 6, while the top end of the columnar spacer 150 is in contactwith two convex portions 131, it is more preferably in contact withthree or more convex portions 131. This is because the columnar spacer150 can be in contact only with the convex portions 131 more stably. Thealignment film 105 is not present at the top end of the convex portion131 in FIG. 6. However, the undesired effect of scraping of thealignment film can be mitigated also in a case where the alignment film105 is not eliminated completely but formed at a small thickness.

FIG. 7 is a plan view showing an example of a place where theconcavo-convex pedestal 130 is formed. In FIG. 7, video signal lines 20are extended in a vertical direction (y direction) and are arranged inthe lateral direction (x direction). Scanning lines 10 are extended inthe lateral direction and arranged at a predetermined pitch in thevertical direction (y direction). The scanning line 10 is used also as agate electrode of the TFT and is formed in a large width. However, fordecreasing the capacitance between the scanning line 10 and the videosignal line 20, a recess 11 is formed at a region intersecting the videosignal line 20 so as to decrease the area.

The drain electrode 21 of the TFT is coupled to the video signal line 20and formed in a horseshoe shape at a portion provided in facing relationto the source electrode 22 so as to surround one side of the sourceelectrode 22. The source electrode 22 is coupled to a pixel electrodenot shown. A semiconductor layer not shown is formed below the drainelectrode 21 and the source electrode 22.

In FIG. 7, the concavo-convex pedestal 130 is extended with apredetermined width W in the lateral direction. In FIG. 7, while onlyone concavo-convex pedestal 130 in a lateral stripe shape is formed inthe lateral direction, it is arranged actually at a predetermined pitchin the vertical direction. The bottom of the concavo-convex pedestal 130is lower than the planarized portion where the concavo-convex pedestal130 is not formed. Further, a convex portion 131 and a concave portion132 which are not shown are formed at the bottom of the concavo-convexpedestal 130.

In FIG. 7, the columnar spacer 150 is disposed at the intersectionbetween the video signal line 20 and the scanning line 10. In FIG. 7,the area of the concavo-convex pedestal 130 is larger than the area atthe top end of the columnar spacer 150. Accordingly, even when thecolumnar spacer 150 should displace laterally, the columnar spacer 150can move only over the convex portion 131 of the concavo-convex pedestal130.

In FIG. 7, the convex portion 131 of the concavo-convex pedestal 130 maybe formed over the entire surface of the bottom of the concavo-convexpedestal 130 or may be formed only at a portion of the area where thecolumnar spacer 150 may possibly displaces laterally. Since theconcavo-convex portion at the bottom of the concavo-convex pedestal 130is formed by half exposure, formation of the concavo-convex portion hasno significant difference in view of the process whether it is formedover the entire surface or only at a portion of the bottom of theconcavo-convex pedestal 130.

In FIG. 7, the pedestal 130 is extended continuously in the lateraldirection in a width W but it may be formed in an island shape only atthe periphery of the columnar spacer 150. However, the continuousconcavo-convex pedestal 130 as shown in FIG. 7 can ensure the degree offreedom for the arrangement of the columnar spacer 150 if this may bepermitted in view of the structure.

Embodiment 2

FIG. 8 is a perspective view showing the shape of the bottom of theconcavo-convex pedestal 130 according to a second embodiment of theinvention. In FIG. 8, a concavo-convex portion at the bottom of theconcavo-convex pedestal 130 is formed only in one direction (xdirection).

That is, in FIG. 8, concavo-convex portions are formed continuously at apredetermined pitch P in the lateral direction (x direction) and ridgesof the convex portions 131 are formed in the vertical direction (ydirection). Also in the shape of FIG. 8, the alignment film 105 is notpresent on the convex portion 131, and the alignment film 105 is formedat a large thickness in the concave portion 132.

In FIG. 8, while the columnar spacer 150 is in contact with the convexportions 131, since the alignment film 105 is not present on the convexportions 131, the alignment film 105 is not scraped off even when thecolumnar spacer 150 should displace laterally. For preventing thecolumnar spacer 150 from tilting and being in contact with the concaveportion 132 where the alignment film 150 is formed at a large thickness,it is necessary that the columnar spacer 150 is in contact with at leasttwo convex portions 131 in FIG. 8.

That is, in FIG. 8, it is necessary that the diameter at the top end ofthe columnar spacer 150 has such a width enough to be in contact with atleast two convex portions 131 in the x direction. Preferably, thediameter at the top end of the columnar spacer 150 is such that the topend is in contact with three or more convex portions 131 in the xdirection.

The angle of inclination θ in the cross sectional shape of the convexportion 131 in FIG. 8 is identical with the case of the convex portion131 having the circular cross section. That is, the cross section in thex direction in FIG. 7 corresponds to the cross section of FIG. 5. Thatis, also in this embodiment, as the condition considering that thealignment film 105 is not formed on the convex portion 131 by theconcavo-convex portion forming process and due to the leveling effect ofthe concavo-convex portion, θ in FIG. 5 is preferably 3 degrees or moreand 45 degrees or less.

When θ is smaller than 3 degrees, the effect of decreasing the thicknessof the alignment film 105 on the convex portion 131 could not beobtained. As the effect of the invention, a predetermined effect can beobtained not only in a case where the alignment film 105 is eliminatedcompletely from the convex portion 131 but also in a case where thethickness of the alignment film 105 on the convex portion 131 isdecreased to less than that on the concave portion 132. The value of θis, more preferably, 6 degrees or more and 25 degrees or less.

In FIG. 8, the extending direction of the convex portion 131 at thebottom of the concavo-convex pedestal 130 or the extending direction ofa ridge 131 is in the y direction, that is, the direction of the width Win FIG. 7. However, the extending direction of the ridge 131 in FIG. 8is not restricted to the y direction but may also be in the x direction.In this case, laterally long ridges 131 are formed at the bottom of theconcavo-convex pedestal 130 extending in the lateral direction shown inFIG. 7, and the ridges 131 are formed at a predetermined pitch in thevertical direction.

Further, the ridge 131 formed at the bottom of the concavo-convexpedestal 131 may have a predetermined angle not only in the x directionor the y direction but also in the x direction and the y direction. Itis important that the top end of the columnar spacer 150 is in contactwith two or more ridges 131, more preferably, in contact with three ormore ridges 131 irrespective of the direction of the ridge 131. In thiscase, it is necessary that the top end of the columnar spacer 150 is incontact with two or more and, preferably, three or more ridges in thedirection orthogonal to the extending direction of the ridge.

Incidentally, the method of injecting liquid crystals in the liquidcrystal display device includes a method of injecting liquid crystalsthrough an injection hole while evacuating the inside of the liquidcrystal display device (vacuum injection method), and a method offorming a sealant at a periphery of the counter substrate and droppingthe liquid crystals to the inside (dropping method: One Drop Fill(ODF)). Of the methods, it is necessary for the dropping method toaccurately control the amount of the liquid crystals to be dropped. Whena large number of the columnar spacers 150 are formed on the countersubstrate 200, control for the dropping amount of liquid crystals isdifficult, and control for the gap between the TFT substrate 100 and thecounter substrate 200 is difficult due to variation of the size betweenthe columnar spacers 150.

Accordingly, in the dropping method, the number of the columnar spacers150 is smaller than that in the case of the vacuum injection method.Then, when the liquid crystal display device undergoes heat cycles, or apressure applied from the outside, etc., the stress and strain exertingper one columnar spacer 150 are increased. That is, the amount oflateral displacement of the columnar spacer 150 is increased. That is,in the case of the dropping method, there is a higher possibility ofcausing scraping of the alignment film.

Accordingly, the effect can be improved particularly effectively whenthe invention is applied to a liquid crystal display device of a type inwhich the liquid crystal is injected by the dropping method.

1. A liquid crystal display device comprising: a TFT substrate having anorganic passivation film; a counter substrate, the counter substratebeing adhered to the TFT substrate by a sealant formed at a peripherythereof; liquid crystals put inside of the liquid crystal displaydevice; a columnar spacer formed on the counter substrate, the columnarspacer defining a distance between the TFT substrate and the countersubstrate; and a concavo-convex pedestal formed in a pixel region of theTFT substrate, the concavo-convex pedestal being provided in facingrelation to the columnar spacer; wherein the concavo-convex pedestal isformed with a convex portion and a concave portion at a bottom of theconcavo-convex pedestal, and the height of the top end of the convexportion is lower than that of the planar portion, wherein the thicknessof the alignment film present on the convex portion is smaller than thethickness of the alignment film present on the concave portion, whereinthe top end of the columnar spacer is in contact with two or more convexportions formed on the bottom of the concavo-convex pedestal, andwherein the area at the bottom of the concavo-convex pedestal is largerthan the area at the top end of the columnar spacer.
 2. The liquidcrystal display device according to claim 1, wherein the top end of thecolumnar spacer is in contact with three or more convex portions formedat the bottom of the concavo-convex pedestal.
 3. The liquid crystaldisplay device according to claim 1, wherein the angle of inclination atthe inclined portion in the cross sectional shape of the convex portionis 6 degrees or more and 25 degrees or less.
 4. The liquid crystaldisplay device according to claim 3, wherein the angle of inclination atthe inclined portion in the cross sectional shape of the convex portionis 3 degrees or more and 45 degrees or less.
 5. The liquid crystaldisplay device according to claim 1, wherein the distance between theTFT substrate and the counter substrate is smaller in the centralportion than at the periphery of the liquid crystal display device. 6.The liquid crystal display device according to claim 1, wherein theliquid crystals are filled by a dropping method.
 7. A liquid crystaldisplay device comprising: a TFT substrate having an organic passivationfilm; a counter substrate, the counter substrate being adhered to theTFT substrate by a sealant formed at a periphery thereof; liquidcrystals put inside of the liquid crystal display device; a columnarspacer formed on the counter substrate, the columnar spacer defining adistance between the TFT substrate and the counter substrate; and aconcavo-convex pedestal formed in a pixel region of the TFT substrate,the concavo-convex pedestal being provided in facing relation to thecolumnar spacer; wherein the concavo-convex pedestal is formed withridges and a concave portion at a bottom of the concavo-convex pedestal,each of ridges being formed by a convex portion extending in apredetermined direction, the concave portion being formed between eachset of the adjacent ridges, wherein the height of the top end of theridge is lower than that of the planar portion, wherein the thickness ofthe alignment film present on the ridge is smaller than the thickness ofthe alignment film present on the concave portion, wherein the top endof the columnar spacer is in contact with two or more ridges formed atthe bottom of the concavo-convex pedestal, and wherein the area at thebottom of the concavo-convex pedestal is larger than the area at the topend of the columnar spacer.
 8. The liquid crystal display deviceaccording to claim 7, wherein the top end of the columnar spacer is incontact with three or more ridges formed at the bottom of theconcavo-convex pedestal.